Method and apparatus for simultaneously forming and heat treating shovels



F. C. BRANDENBURG METHOD AND APPARATUS FOR swummznusmr' FORMING AND HEAT TREATING'SHOVELS Filed Jan. 1921 2 Sheets-Sheet l i INVENTOR.

' C. @Mwm MW ATTORNEY,

July 8, 1924.

F. c. BRANDENBURG METHOD AND Filed Jan. 17.

APPARATUS FOR smuurmsnusm FORMING AND HEAT TREATING SHOVELS 2 Sheets-Sheet 2 INVENTOR.

ATTORNEY.

Patented July 8, 1924.

Emir-n stares l thhfill FRANCIS o. BRANDENBURG, or Pietra, OHIO, ass elvoa'ro wooD sHovEt. AND TOOL COMPANY, or PIQUA, OHIO. AooRPoRATroN or OHIO.

METHOD AND ArPARA'rus Foe s'IiviiiLrKNnousLY roitmniie AND HEAT TREATING sHovELs.

"Application filed Jan-nary 17, 1921. Serial No. 437,764.

of my present invention is to maintain a pre- 7 determined form in the shovel during its h'eat-treatment, not only to overcome the tendency of the metal to warp, but to endow the metal with a capacity for resisting strains which tend to distort it. Another object is to reduce the labor and therefore the expense involved in heat-treating shovels, particularly in that no straightening must be done on the shovels after they are heat-treated. Another object is to impart to the sl'iovels their final form after they are immersed in the quenching bath and theii maiiitaining that form while the metal is being chilled in the quenching bath;

For the purpose'of eiie'ctinpthe above mentioned objects, and in cider to carry out certain details, tobe referred to presently, I have devised certain apparatus, which consists, briefly, in a pair or clamping jaws or dies mounted on a suitable frame and immersed in the quenching bath, in which a heated shovel may be inserted as it is plunged into the bath. A lever connected to the dies with powerful toggles is provided by which theshovel may. be quickly and tightly clamped between the dies, so that before the metal of the shovel has cooled below the critical temperature it is given the form it is to have when finished, and is maintained in that form until it is cooled.

In the accompanying drawings- Figure 1 is a perspective View of my ap paratus, including the tank, shown in dotted lines, for containing the quenching bath.

Figure 2 is another perspective view, seen fromja different point of view and with the machine removed from the tank.

Figure 3 is a sectional elevation of the dies and parts supporting them, showing a fragment of a shovel clamped between them.

Figure 4 is a view of a shovel, showing a camber near its cutting edge, which throws the cutting edge down; i. e., toward the ground-as the shovel is used. This camber isput in the shovel after it is plunged into th'ebath, but before it cools below the critical temperature of the metal.

The apparatusv or machine, comprises a frame composed of two bars 10, joined near one end by a cross bar 11 andat the other end with an angle 12. Fixed to the angle 12 are two guide rods 13, on which a second angle 14 is mounted to slide. The angle is kept from wabbling on the rods by uiding ears 15 riveted to the angle. A root shaft 16, journaled on the frame, carries arms 17, which are connected by links 18 to the angle 14, thus forming a toggle arrangement by which the angle 14 may be moved to and fro with reference to the angle 12. The shaft 16 is rocked by a lever 19. A spring 20 tends to move the angle 14 away from angle 12.

A die or jaw 25 is secured to angle 12 by 'means of knees 26. The die is T shaped,

the stem of the T being used for its support. This die is made long enough, preferably, to adapt it to the broadest shovel, but it may be used for narrower ones, as well. A similar T shaped die 27 is secured to the angle 1 1 with knees 28, so'that the stems of the two Ts lie iii the same plane. One side of the head of T 27 is excessively wide, how ever, and extends abuts the corresponding part of the opposing head. The opposed faces of the dies aresubstantially flat and parallel, so that the portion of the shovel clamped between them will be maintained fiat. The extended part of the die 27, which I have indicated by the numeral 29, is bent at a point about even with the -edge of the die 25, so that it leans toward the die 25. WVhen the shove-l is clamped between the dies, thep'ortion of the shovel which is actually confined between them is held fiat and straight while the portion above the die 25 is bent back by the extension 29, forming a camber in the shovel at 30 which throws the cutting edge downward. The die 27 is made of a suitable length to enter between the side flanges 31 of the shovel and is preferably rounded at its ends to fit in between the flanges.

A rigid arm 35, attached to the angle 14, carries an adjustable stud 36. As the dies close in on the shovel this stud bears against the shovel at a point considerably above the dies and assists the extension 29 in making the bend. While this stud is not essential it is very useful. It not only relieves the dies, especially the extension 29, of considerable strain, but it also tends to bring about uniformity in the work done by the dies. It effects this result by providing a fixed point,a sort of gauge, against which each shovel must bear, and since the gauge is far removed from the dies it insures the shovel being in a definite and predetermined position with reference to the dies, and opposes whatever tendency there may be for the metal to warp while it is being chilled by the quenching bath. Finally, by adjusting the stud in or out with reference to the arm 35 a reasonable variation in the degree of camber. imparted to the shovel may be obtained with a single pair of dies.

This apparatus is suspended in .a tank filled with suitable quenching liquid. In Figure 1 the tank is shown diagrammatically and it will be seen that the frame is extended at one end so that it can rest on the wall of the tank, stop pins 40 being provided to keep it from slipping off. The other end of the machine is supported by a bar 41, which hooks on the wall of the tank and is adjustably attached to the angle 12. I

The shovels are heated to a degree above the critical temperature of the metal and inserted between the dies, which are then pressed together with the toggles operated by the lever. It is necessary, of course, to get the shovel into place between the dies and bring the dies together very quickly, as otherwise themetal will be chilled by the quenching bath before it is formed. To facilitate the insertion of the shovel between the dies and insure its being in the proper position, all without loss of time,

I provide certain guides which will now be described.

Two uprights are adjustably bolted to the angle 12, and carry broad guide plates '46. The sides of the shovel bear against these as it enters the bath, and the guides are preferably set close enough so they hug the shovelfslightly as itmoves between them. The guides are flexible enough, however, to

and as he thrusts the shovel into the bath a the operator presses it gently against the guides, thereby causing it to enter the space between the dies without touching either of them. Attached to the horizontal leg of the angle 14 are stops 48, on which the end, or what I call the cutting edge, of the shovel is rested as the dies are closed. As the dies come together the guides 47 yield and are pushed back by the shovel to the position they occupy in Fig. 3.

It is unnecessary to dwell much on the effect of the quenching bath, as that is well understood. The facilities for entering and clamping the shovel between the dies, quickly, enable the operator to do this while the heat of the metal is still above the critical temperature. The toggle mechanism and lever afford ample power with which to clamp the shovel, and even form the camber in it. The camber has two principal purposes; first, it stiffens the shovel and keeps the cutting edge straight, and second, it throws the cutting edge below the plane of the bottom of the shovel and insures the cutting edge being on the ground as the shovel cuts under the material it is to lift. Holding the metal in the position it is to retain while it passes the critical or Ar point, prevents its warping. Although part of the metal is confined between thedies while the remainder is exposed to the direct action of the quenching liquid, unequal chilling is avoided by the fact that the dies are constantly immersed in the liquid and are therefore maintained at about the same temperature as the liquid. The dies are of light, skeleton like, structureand to make them still sensitive their faces are slotted, so as to reduce them to a succession of freestanding vertical fingers, the gravity cir culation of the quenching liquid being thereby facilitated, resulting in a very effective dissipation of the heat. This is well shown in Figure 2, and it is clear that the vertical spaces between the fingers, together with the shovel form channels through which the heat of the shovel quickly sets up a current, thereby constantly bringing cooler liquid into contact'with the shovel and the die members.

lVhile my new method is preferably directedto the purpose described, it is'by no means limited to such. If desired the shovels may be camber-ed before they are heated, and the dies merely used to retain the form previously given to them. On the other hand, shovels may be heat-treated by my method and with apparatus similar to that described, but without giving them the camber. It is to be noted that, notwithstanding the entire shovel is subject to warp-ing, I do not undertake to restrain it where warping will do no harm. That is, the. entire bowl of the shovel is liable to warp, but 'since shovels do not have to conform to an exact standard in the matter of form, I limit my control to those parts where some precision and uniformity is required. Furthermore, the bowl shape which is given to the shovel is comparatively stable and not much affected by the heat treatment. But the camber is not so stable, partly because of the bend being so slight and partly because it conflicts with the bowl shape of the shovel. However, it is found that even the limited restraint described affects indirectly and favorably the entire shovel, with the result that shovels heattreated by my method are more uniform in contour than those otherwise heat-treated.

It is evident that apparatus for carrying out my method of heat-treatment need not b restricted to that described, as modifications of various kinds may be made without departing from the principles I employ. Furthermore, although I have described my method only in connection with heattreating shovels, it is obvious that the same method with necessary modifications is applicable to the heat-treatment of other artic-les.

VVhat- I claim is as follows:

1. The method of heat-treating a shovel which comprises heating it and immersing it in a quenching bath, immediately thereafter confining a comparatively narrow zone, including the cutting edge, in a clamping 'device which is also submerged in the bath, whereby said zone is held until the metal cools in the form it is required to have, the remaining submerged portions be ing left unconfined while the cooling takes place.

2..The method of heat-treating a shovel, which comprises heating the shovel and while hot immersing it in a quenching bath, clamping portions of it in jaws immersed in the bath while other portions simultaneously receiving heat treatment are left unconfined, allowing the shovel to remain thus while it cools.

3. The method of forming and heattreating a shovel, which comprises preformi'ng portions of the shovel, then heating the shovel and immersing it in a quenching bath, forming portions of the shovel after it has been immersed in the quenching bath, but before the metal has cooled.

4. The method of forming and heattreating a shovel, which comprises pre forming such portions of the shovel as are not liable to become distorted when heated for heat-treatment, then heating the shovel,

plunging it into a quenching bath and forming portions of the shovel while submerged but before the metal has cooled, maintaining the form thus imparted until the metal has cooled.

5. The method of forming and heattreating a shovel, which comprises heating the shovel and plunging it into a quenching bath, forming portions of the shovel after it has. been immersed but before the metal has cooled, said formation being effected partly. by direct confinement of the metal to the desired form and partly by the indirect effect of such confinement.

6. The method of forming and heattreating a shovel, which comprises heating the shovel and plunging it into a quenching bath, forming portions of it after it is immersed but before the metal has cooled, the shovel being automatically guided to the position it occupies while being formed and allowed to remain in said position until the metal has cooled.

7. The method of heat-treating a shovel, which comprises heating the shovel and immersing it in a quenching bath, immediately confining portions of the blade and holding in confinement until the metal has cooled, said confinement being effected in such a manner as to withdraw a comparatively small area of the surface from the direct action of the quenching iiquid and so as to permit free circulation of the liq uid vertically.

8. Apparatus for simultaneously forming and heat-treating metal products, comprising a pair of forming dies, means for clamp ing'the products between said dies with sufficient force to impress the form of the dies on the products, a vessel containing quenching liquid, in which said dies are immersed, and means for operating the dies while immersed in said liquid.

9. Apparatus for heat-treating shovels, comprising a pair of dies adapted to clamp a portion of a shovel between them and hold said portion in a predetermined form while the heated shovel is being chilled, a vessel containing a quenching liquid, said dies being immersed in the liquid, the liquid submerging not only the portion of shovel clamped in the dies but the remainder of the shovel as well, means for guiding the shovel to its proper position between the dies, so that it may be placed between them quickly, and means for operating the dies while immersed.

10. Apparatus for simultaneously forming and heat-treating a shovel, comprising a pair of dies whereby to form a camber in the end of a shovel near its cutting edge and parallel therewith, said dies being immersed in a quenching bath; guides for directing the shovel to the proper position between the jaws, stops to arrest the shovel when it reaches the proper position and means for closing the jaws after the shovel is in place.

11. Apparatus for simultaneously forming and heat-treating a shovel, comprising a pair of dies whereby to form a camber in the end of a shovel near its cutting edge and parallel therewith, said jaws being immersed 'n a quenching bath, and having numerous vertical slots in their gripping faces to allow the quenching liquid to reach a large part of the area which is between the jaws; and means for operating the jaws without withdrawing them from the bath.

12. Apparatus for simultaneously forming and heat-treating a shovel, comprising a pair of forming jaws whereby to make a bend in-the shovel near and parallel with its cutting edge, one of said jaws beingbroader than the other and comprising two faces at the angle with reference to each other that it is desired to impart to the bend in the shovel, the other jaw being arranged to cooperate with one of said faces to grlp the shovel, while the other face makes the bend; a quenching bath in which said jaws are constantly immersed and means for operating the jaws while immersed.

13. Apparatus for simultaneously forming and heat-treating a shovel, comprising a pair of forming jaws whereby to make a bend in the shovel near andparallel with its cutting edge, one of said jaws being narrower than the other, and adapted to engage the bottom of the shovel between the cutting edge and bend, the other jaw having a face adapt-ed to cooperate with the narrow jaw to clamp the shove], the excess of width of said jaw extending above the bend and the face thereof forming an angle with reference to the part which cooperates with the narrow jaw corresponding substantially to the degree of bend to be imparted to the shovel; an abutment movable with said broad jaw, whereby the major party of the shovel is pushed over as the jaws come together, to assist the extending part of the broad jaw in making the bend; a quenching bath in which said jaws are im mersed and means for operating the jaws.

14. Apparatus for simultaneously forming and heattreating a shovel, comprising a frame, a forming jaw fixed thereto, a movable jaw, guides therefor, a toggle connection between said jaw and the frame whereby to move said jaw with reference to the fixed jaw; side guides whereby to direct the shovel into the proper position with reference to the jaws, and guides to prevent the shovel striking the jaws as it is inserted between them'these guides being yielding so as not to interfere with the functioning of the aws when they close; and a quenching bath in which said mechanism is immersed.

15. Apparatus for simultaneously forming and heat-treating a shovel, comprising" a frame, a forming awfixed thereto, amovtion with reference to the jaws on being 7 inserted between them, a quenching bath in which said mechanism is immersed, and means for operating the jaws while they are immersedin the bath.

16. Apparatus for simultaneously form-r ing and heat-treating a shovel, comprising a frame, a forming jaw fixed thereto,a carriage mounted to slide on the frame to and fro with reference to said jaw, means for moving the carriage, a forming jaw mounted on the carriage to cooperate with the fixed jaw for forming the shovel, an arm on the carriage adapted to bear against the shovel above the jaws and pushthe shovel over toward the fixed jaw, thereby'assisting the jaws to put a slight camber in the shovel between them, guides for directing the shovel to the proper place with reference to the jaws, aquenching bath in which said mechanism is lmmersed, and means for mov ing the carriage while said mechanism is immersed. l

17. Apparatus for heat-treating a shovel, comprising a pair of aws between which to clamp the shovel while in the quenching bath, said jaws being T shaped in cross section, the stem of each support for the jaw and the head as the clamping member, said heads being slotted,

transversely so as to form a plurality of free-standing fingers; and means for operat-i ing said jaws while immersedin the quenching bath. 7

18. Apparatus for heat-treating a shovel, comprising a pair of jaws between'which to clamp the portion of'the shovel adjacent to" its cutting edge and hold said portion in a predetermined form while the shovel is in the quenching bath, a frame on which said jaws are mounted, a tank containing quenching liquid, meansfor suspendingsaid frame in the tank with the jaws immersed in the liquid, guides for directing theshovel to its proper position between the jaws, and means for operating the jaws to clamp a shovel after the shovel is immersed in the liquid said means being quick acting, so that the shovel can be clamped before it'has cooled too much.

Framers c. BRANDENBURG.

T acting as the- 

